Specialists are working to stabilise a wall at Higham Ferrers' Chichele College after a section of it came down.
College Street in the town is currently closed after stones came away from the college's perimeter wall over the weekend.
A spokesman for Higham Ferrers Town Council said: "Over the weekend there was a stone fall from the inner side of a historic perimeter wall at Chichele College.
"The masonry fell onto the college's garden.
"As a necessary safety precaution, the police have closed College Street, as well as the pavement, to protect the public from the risk of further falling masonry.
"Specialists from English Heritage are now working to ensure that the wall is stabilised."
A spokesman for Northants County Council told the Northants Telegraph: "We are aware of the collapse of a wall on Higham Ferrers High Street and we closed the road for safety purposes.
“English Heritage own the building and East Northamptonshire Council are carrying out the structural surveys.
"The road will remain closed until it is safe to re-open.
"Pedestrians are advised to use the footway on the other side of the A5028.”
A spokesman for East Northants Council told the Northants Telegraph today (Thursday): "Following the incident, ENC’s building control team were alerted as the wall had been classed as a dangerous structure and officers attended the site to check all was in order and there was no further danger to the public.
"Upon attending the site, officers confirmed necessary precautions had already been put in place to protect the public and once remedial work has been completed and inspected, the case can be closed.
"ENC are quite happy with how everything has been handled and everyone involved has been helpful to ensure the situation is resolved as quickly as possible."
Message from the editor:
Thank you for reading this story on our website. While I have your attention, I also have an important request to make of you.
In order for us to continue to provide trusted local news on this free-to-read site, I am asking you to also please purchase a copy of our newspaper.
Our journalists are highly trained and our content is independently regulated by IPSO to some of the highest standards in the world. The dramatic events of 2020 are having a major impact on many of our local valued advertisers and consequently the advertising that we receive.
We are now more reliant than ever on you helping us to provide you with news by buying a copy of our newspaper.